One already knows fuel cells of this type, in which the distributors consist of electrically conducting plates made for example from graphite and in that face of which, which is in contact with the electrode, are formed channels for the circulation of the gases constituting the reagents.
These distributors exhibit the inconvenience that the channels prevent at their uprightness the electronic contact between the plate and the electrode and that in addition the access of the gases to the electrodes is limited to the open surface of the channels.
One further knows fuel cells in which the distributor plates are made from an electrically conducting porous material. These plates exhibit the advantage of broadening the reaction zone of the electrodes with respect to the plates with channels but exhibit the inconvenience that owing to the diagonally opposite arrangement of the gas inlet and outlet, the mean path of travel of the latter corresponds only to one fraction of the surface of the electrode. As a matter of fact, the distribution by porous materials may be likened to the putting in parallel of a great amount of channels with a very reduced section and low-pressure loss. Due to this fact, the gas behaves like an electronic current and follows the shortest path of travel from the inlet towards the outlet of the reagent while leaving aside substantial portions of the porous material remote from the optimum path of travel.
The object of the present invention is to propose a fuel cell which does not exhibit the inconveniences, which have just been set forth, of the known fuel cells.
To reach this goal, the fuel cell according to the invention is characterized in that each plate consists of a stack of foils of porous material, adapted to be travelled over in series by the reagent gas.
According to one characterizing feature of the invention, the foils are impervious to the reagent gas at those sides which are in contact with other foils and at that face which is not in contact with the electrode.
According to another characterizing feature of the invention, the adjacent foils of porous material are made impervious to the gas at their mutually facing sides by sheets of materials impervious to the gas and interposed between the foils.